Process of decomposing sulphides



35 ency to do so.

Patented Nov. 6, 1923.

4 UNITED STATES PATENT -Friea.

MATHIAS OVROM SEMI, OF CHRISTIANIA, NORWAY, ASSIGNOR TO DIE! NOBSKE AKTIESELSKAB FOR ELEKTROKEMISK I NDUSTRI, OF CHRISTIANIA, NORWAY.

PROCESS OF DECOMPOSING SULPHIDES.

No Drawing. Original application filed January 31, 1918, Serial No. 214,718. Divided and this application filed December 9, 1919. Seril No. 343,566.

To all whom it may concern:

Be it known that I, MA'I'HIAS OVROM SEM, a subject of Norway, and a resident of Christiania, Kingdom of Norway, have in- 6 vented certain new and useful Improvements in the Processes of Decomposing Sulphides, of which the following is a specification, this application being filed as a continuation of my application Sr. No. 214,718, 10 filed January 31, 1918.

This invention relates to the treatment of complex sulphides chiefly for the recovery of metals therefrom by a selective action on the sulphides of a substance which alloys principally with only certain of the metals therein.

I have found that sulphide ores may be partly or wholly decomposed and the metals recovered by heating in the presence of such an alloy-forming material, which is supplied during the process, and that certain of the metals may be separated from the other metals of the sulphides by a proper selection of the alloy-forming material.

2 The sulphur liberated by decomposition, in

part as free sulphur and in part as com-.

bined sulphur, Wlll volatilize and may be removed from the furnace in any suitable manner and the vapor further treated if desired for the recovery of pure sulphur therefrom. I

As an example, iron, nickel and cobalt will readily alloy with silicon, but. copper and the noble metals have no great tend- If, therefore, an ore containing both iron and copper sulphides is treated according to my invention with ferrosilicon, or other silicon compounds or alloys, as an alloy-forming material, the iron 40 liberated will dissolve therein while the sulphide matte will become concentrated in copper. If nickel sulphide is present in the ore, the nickel will dissolve together with the iron and form ferronickel-sillcon.

From an industrial standpoint, my process will probably be of the most importance in connection with sulphides containing copper associated with the sulphides of iron or nickel or both, and in illustrating the process I will accordingly make use of such selection made. I will furthermore, and

with the same understanding, make use of ferrosilicon as the alloy-forming material,

Considering first the process employed with an iron copper sulphide, the following is an illustration of its application thereto About 500 kg. of iron sulphide ore containing: -4=4% Fe, 1.2% Cu, and 48% S is brought into a furnace, preferably an electric furnace, with 50 kg. of ferrosilicon (50% Si) and heat is applied. At a temperature of 1185 C. the iron sulphide will melt and flow to the bottom of the furnace.

The FeS present will first decompose and form FeS and S, and the FeS will then decompose until the following equilibrium is established FeSsFe S But the ferrosilicon will immediately dis-. solve or extract the free Fe, thereby disturbing the equilibrium and causing the-decomposition of more FeS. The above action will take place to some extent at 1185 C. but I prefer to employ temperatures ranging from about l450- to 1500 C., as the ferrosilicon and the sulphides will then be in a molten state, the ferrosilicon bath because of its greater specific gravity being beneath the sulphides. If suflicient ferrosilicon is present the decomposition may be carried to any desired extent.

The copper sulphide present will also decompose giving theequilibrium cus:cu+s,

but the decomposition will not take place to any considerable extent as long as there is present'an excess of iron. The amount of copper which will dissolve in the ferrosilicon depends upon the concentration of 95 copper in the molten sulphides. Therefore thedec'omposition of the sulphides should not be carried so far that the ferrosilicon will dissolve the copper to such an extent as to prevent it being used in the iron industry. I prefer to carry the decomposition of the sulphides so far that the final con' Having reached the desired concentration of Cu in the undecomposedsulphides,

which may conveniently be determined by sampling, I stop the treatment and remove the ferrosilicon and the remaining sulphides from the furnace.

As the result: of my treatment Lrobtain about 240 kg. of ferrosilicon containing ap roximately 510% Si and 0-4f 1 S, an about 50 kg. of matte containing approximately 20% Cu. 7

The ferrosilicon is in a condition suitable for the manufacture of high per cent ferrosilicon or it may be desulphurized according to known processes and used for the manufacture of iron and steel.

My process may advantageously be carried out continuously, the charge being supplied with the necessary amount of ferrosilicon. The furnace must in this case be rovided with an arrangement for tapping errosilicon and matte, such, for example, as is illustrated in Fig. 74 on page 166 of Stansfield 'The Electric Furnace, published by Mo- Gr'aw-Hill Book Company'Inc. 1914.

While the above is a simple illustration of the carrying out of my process, it is advantageous to have the sulphides as pure and as concentrated as possible, and therefore in most cases a preliminary smelting treatment of the suphide ore is desirable, whereby the sulphides are separated from the gangue and resultant oxide. Such preliminary smelting may be carried out continuously in the furnace above referred to,

and the comparatively pure sulphides thus obtained may be transferred to another furnace such, for example, as illustrated in the aforesaid work by Stansfield in Fig.

94.- on page 221 thereof, in which the further treatment is carried out intermittently. The size of this furnace must of course be so adjusted as to take care of all the sulphides from the first furnace in which the preliminary smelting takes place. Instead of a single furnace I may employ several for the treatment of the sulphides.

I A preliminary treatment of the ore in a separate furnace is particularly advantageous when the ore to be treated contains in addition to the sulphides'of iron and copper, another sulphide such as nickel sulphide. When the nickel sulphide is decomposed by treatment according to my process the metallic nickel will dissolve in the ferrosilicon present, forming ferronickel silicon which is a valuable product, the value varying with the nickel content.

By treating in this manner, 'at the preferred temperatures heretofore mentioned,

By decomposing this with ferrosilicon a ferronickel silicon resulted which contained Per cent.

Fe 57 Ni 25 Cu r 1.2

Sin 17 The remaining matte contained t Per cent. Fe 39 Cu 25 Ni 8 S 32 When it is desired to form an alloy particularly rich in nickel, it is advisable to remove as much of the iron as ossible by the preliminary treatment. Such a treatment may for instance be a combined roasting and smelting of the sulphide ore, by which it is possible to remove practicallyv allof the iron. In such a case the sulphidesto be treated. according to my process comprise a matte of the sulphides of nickel and copper. The decomposition of the copper sul hide efl'ected is regulated by the-amount-o silicon present and will accordingly not take place to any considerable extent so long as there is present an excess of nickel. In this concentrated nickel copper matte the sulphur content is of comparatively little value and its recovery may be disregarded.

It should be understood, however, that my process may also be carried out in a single operation, in which case the ferrosilicon will be added to the furnace in which the sulphide ore is melted, and the temperature of the furnace preferably be maintained at about 1450 to 1500 C. L

From the foregoing explanation it will be understood that my process may be car ried out with various materials, and possesses great advantage when compared with the metallurgical processes at present emplolyed in the treatment of such materials. he foregoing detailed description has been given for clearness of understanding and no undue limitation should be deduced therefrom, but the appended claims should be construed as broadly as permissible in view of the prior art.

What I claim as new and desire to secure by Letters Patent, is:

1. The process of treating complex sulphides for the selective recovery of metals thereform, which comprises subjecting the sulphides to heat in the presence of a substanop which alloys principally with only certam of the metals present and at such tem ratures that decomposition of the sulphi es of the alloying metal is effected and an alloy thereof formed.

2. The process of treating complex sulphides for the selective recovery of metals and sulphur therefrom, which comprises subjecting the sulphides to'heat in the presence of a substance which alloys principally with only certain of'the metals present and at such temperatures that decomposition of the sulphides of the alloying metal is effected, formin an alloy of the alloying metal with the said substance, forming a matte of the undecomposed sulphide, and vaporizing and conducting away the liberated sulphur.

3. The process of treating complex sulphides for the selective recovery of metals therefrom, which comprises subjecting the sulphides in a molten state to the action of a substance which alloys principally with only certainof the metals present and at such temperatures that decomposition of the sulphides of the alloying metal is efiected and an alloy thereof formed.

4. The process of treating complex sulphides for the selective recovery of'metals therefrom, which comprises subjecting the sulphides in a molten state to the action of a substance also in the molten state which alloys principally with only certain ofthe metals present and at such temperatures that decomposition of the sulphides of the alloying metal is effected an alloy thereof formed.

5. The process of treating. complex sulphides containing iron and copper for the selective recovery of the said metals therefrom, which comprises subjecting the sul- .phides to heat in the presence of a substance which alloys principally with the iron and at such temperatures that decomposition of the iron sulphide is efiected and an alloy of thcviron formed.

6. The process of treating complex sulphides containing iron and copper for the selective recovery of the said metals therefrom, which comprises subjecting the sulphides to heat in the presence ofsilicon at such temperatures that decomposition of I the iron sulphide is effected and an alloy of the iron formed.

7. The process of treating complex sulphides containing iron and copper for the selective recovery of the said metals therefrom, which comprises subjecting the sulvaporizing and conducting away the liberated sulphur.

9. The process of treating complex sul-.

phides containing iron, nickel and copper for the selective recovery of the said metals therefrom, which comprises subjecting the sulphldes to heat in the presence of a substance Which alloys principally with the iron and nickel and at such temperatures that decomposition of the iron and nickel sulphides is effected-and an alloy of the iron and nickel formed.

10. The process of. treating complex sulphides containing iron, nickel and copper for the selective recovery of'the said metals therefrom, which comprises subjecting the sulphides to heat in the presence of silicon and at such temperatures that decomposition of the iron and nickel sulphides is effected and an alloy of the iron and nickel formed.

11. The process of treating complex sulphides containing iron, nickel and copper for the selective recovery of the said metals therefrom, which comprises subjecting the sulphides to heat in the presence of ferrosilicon and at such temperatures that decomposition of the iron and nickel sulphides is eflected and an alloy of, iron and nickel formed.

12. The process of treating complex s'ul ing metal is effected and an alloy thereof formed.

14. The process of selectively recovering,

iron, nickel and copper from sulphide ore containing the said metals, which comprises subjecting the ore to a. smelting treatment whereby a complex sulphide matte of the said metals is produced, subjecting the guiphide matte to heat in the presence of silicon and at such temperatures that decomposition of the iron and nickel sulphides is effected and an alloy of the said metals formed.

15. The process of selectively recovering iron, nickel and copper from sulphide ore containing the said metals which comprises subjecting the ore to a smelting treatment whereby a complex sulphidematteof the said metals is produced, subjecting the sulphide matte to heat in the presence of ferrosilicion and at such temperatures that decomposition of the iron nickel sulphides is effected, forming an alloy of the iron and nickel with the ferrosilicon, concentrating the undecomposed copper sulphide in the resultant matte, and vaporizin and conducting away the liberated sulp ur.

16. The process of treating sulphide ore containing iron, nickel and copper for the selective recovery of nickel and cop ertherefrom, which comprises subjecting t e ore to a roasting and smelting treatment for the separation of iron therefrom, subjecting the resultant sulphide matte containing nickel and copper to heat in the presence of a. substance which alloys principally \vithiithe nickel and at such temperatures that decomposition of the nickel sulphide is effeited and an alloy of the nickel formed.

17. The process of treating sulphide ore containing iron, nickel and copper for the selective recovery'of nickel and copper therefrom, which comprises subjecting the ore to a roasting and smelting treatment for the separation of iron thereform, subjecting the resultant sulphide matte containing nickel and copper to heat'in the'presence of silicon and at such temperatures. that decomposition of the nickel sulphides is effeetedand an alloy of the nickel formed.

18. The process of treating sulphide ore containing iron, nickel and copper for the selective recovery of nickel and copper thereerated su from, which comprises subjecting the ore to a roasting and smelting treatment for the separation of iron therefrom, subjecting the the ferrosilicon, concentrating the unde- 1 composed copper sulphide-in the matte, and vaporizinigand conducting away the libphur.

19. The process of treating complex sulphides of iron and copper for the selective recovery therefrom of a material comprising iron and copper in definite proportions, which comprises subjecting the sulphides in a. molten state to heat in the presence of silicon at such tein ratures that decomposition of the sulphi es is effected, regulating the amount of copper sulphide decomposed bythe quantity of silicon supplied, forming an alloy of'the liberated iron and copper, separating the undecomposed copper sulphide therefrom by the formation of a matte of the said sulphide, and vaporizing and conducting awaythe' liberated sulphur,

20. The process of treating complex sulphides of iron and copper for the selective re; overy therefrom of a material comprising Iron and copper in definite proportions, which comprises subjecting the sulphides in a molten state to heat in the presence of ferrosilieon at such temperatures that decomposition of the sulphides is effected, regulating the amount of copper sulphide decomposed by the quantity of ferrosilicon supplied, forming' an alloy of the liberated iron and copper with the ferrosilicon, separating the undecomposed copper sulphide therefrom by the formation of a matte of the said sulphide, and vaporizing and conducting away the liberated sulphur;

21. The process of treating complex sulphides of iron, nickel and copper for the selective recovery therefrom of a material comprising iron, nickel and a definite proportion of'copper, which comprises subjecting the sulphides in a molten state to heat in-the presence of silicon at such temepratures that decomposition ofthe sulphides is effected, regulating the amount of copper sulphide decomposed by the quantit of silcon supplied, formin an alloy 0 the liberated iron, nickel and copper, separating the undecomposed copper sulphide therefrom by the formation of a matte of the said sulphide, and vaporizing and conducting away the liberated sulphur.

22. The process of treating complex sulphides of iron, nickel and copper for the selective recovery therefrom of a material comprising iron, nickel and a definite pro portion of copper, which comprises subeat in the presence of ferrosilicon at "such ilecting the sulphides in 'a molten state to temperatures that decomposition of the sulformation of a matte of the said sulphide,

phides is effected, regulating the amount of and vaporizing and conducting away the copper sulphide decomposed by the quantiliberated sul hur.

ty of ferrosilicon supplied, forming an alloy Signed at ew York, N. Y., this 6th day, 5 of the liberated iron, nickel and copper with of December, 1919.

the 'ferrosilicon, separating the undeoomposed copper sulphide therefrom by the MATHIAS OVROM SEM. 

